1. Field of the Invention
The invention concerns an omnidirectional wheel and a method for installing roller bodies of an omnidirectional wheel, as well as an omnidirectional movable chassis embodying such an omnidirectional wheel.
2. Description of the Prior Art
The prototypical of an omnidirectional wheel is known from DE-OS 21 58 019. Such wheels can be used to move vehicles in any desired direction without having to be borne in a pivoting fashion on the vehicle. Two forward and two rear rotating drive arrangements can thereby be provided that respectively possesses an omnidirectional wheel. The drives are individually controllable and the rollers contacting the floor are arranged at an angle, wherein a first diagonal pair of wheels respectively runs at an angle in the same direction and a second diagonal pair of wheels runs inclined at a right angle to the first diagonal pair.
In WO 2007/016917 A2 an omnidirectional wheel is disclosed that has a wheel hub that can be rotated around a rotation axis, wherein two wheel discs connected with the wheel hub are arranged coaxial to the wheel hub, and a number of rounded roller bodies are provided that are arranged between the wheel discs, are distributed uniformly along a circumferential shell of the wheel and are aligned with their roller axes at a diagonal angle to the rotation axis of the wheel hub. On their opposite ends the roller bodies are borne such that they can rotate freely relative to the wheel discs. The roller bodies are borne (via associated bearings) directly on the insides of the wheel discs. This has the disadvantage that all bearing positions must be matched to one another in terms of production so that all roller bodies are positioned concentrically and symmetrical to one another without position deviations. As a result the installation of such wheels is complicated since the precise positions of the roller bodies must be adjusted repeatedly and laboriously during the installation. Moreover, even given proper use a high moment applied to the omnidirectional wheel can produce a torsion of the hub that causes a rotation movement of the one wheel disc relative to the second wheel disc, whereby all adjusted bearings of the roller body can experience a displacement. However, the use of opposing wheel discs between which the roller bodies are arranged has proven its worth.
On the periphery these wheels have rollers that are aligned at a 45° angle to the rotation axis. The surface of the rollers is curved so that the circumferential surface on which the wheel rolls describes a circle. The support structure of these wheels is formed by the two side walls. The rotation axes of the rollers are positioned by the bearing surfaces in the side walls. An axial offset of the two guides in which the rollers are borne results via a rotation of the two side walls relative to one another. This applies for all rollers. This leads to problems with the bearing of all rollers. The support points at both side walls for all rollers on the periphery of the wheel must be aligned towards one another in pairs, and the axes of the bearing points must align relative to one another. If this is not the case, an axial offset of the bearings of individual wheels results, which leads to problems with the bearing of these rollers, which should be avoided. Therefore in the prior art the side walls must be produced with narrow tolerances.